Sunday, 9 August 2009

Tiny galaxies, enormous atoms, and people at the centre of it all...

Literary fiction usually only portrays human characters. This type of fiction places humans at the centre of what is an inhuman universe. It hasn’t absorbed the lesson of the Copernican revolution.

In contrast, since Copernicus’s models and Galileo’s observations, science thinks it fully understands that the universe was not built for us (leaving aside any discussion of the anthropic principle - I’ll save that for another day).

Science deals with physical and temporal phenomena on all scales. The way we define a second of time uses gaps between energy levels in atoms. Stars and galaxies were created billions of years ago.

But I wonder if scientists still sneakily use humans and human-sized experiences as the ultimate measuring scale.

It’s common in astronomy to use redshift as a proxy for distances to galaxies. This is because redshift is the only direct measurement of distance without any reference to, or reliance on theoretical models of the universe. But it also happens to be a simple number without any units (because it is a ratio), and for all measurements apart from one, it is currently between 0 and 10. The only redshift measurement which is higher than this is for the cosmic microwave background, which is at a redshift of 1000.

So, when you’re at a telescope, measuring the redshifts of quasars, you don’t think about the fact that they were formed billions of years ago and are billions of light-years away (the word ‘are’ is a bit tricky in this context – you’re seeing them as they were then, not as they are now). They have redshifts of 1, 2, 3, 4 – numbers you learnt in primary school.

The same goes for size. Astronomers look at images of galaxies that are small enough to fit onto their computer screen. They used to use glass plates to take images of large parts of the sky. Just one of these plates, which are 8 inches square, would show around 100,000 objects – both stars and galaxies. So there was a curious inversion of size, we had to look at these plates with an eyepiece to see the details of the galaxies, the curved spiral arms, the wisps of gas. In every single astronomical imaging there is a huge compression ratio of what is actually out there to what we can cope with.

The list goes on and on… Physicists use a unit called a ‘barn’ to refer to the cross section of an atomic nucleus. When this was first calculated in the 1940s, people said that it was ‘as big as a barn door’.

There is a lovely poem on the Human Genre Project which compares the images of chromosomes to teeth. Again – bringing the not quite human into our world.

Are there drawbacks to this? It means the Copernican revolution is not finished. So when Richard Dawkins tries to explain to us that our behaviour is governed by genes, we still cannot accept that loss of free will. And while science is still struggling, literary fiction hasn’t even begun to come to terms with this.


  1. Interesting post - but I don't agree that Dawkins says our behaviour is governed by genes, or that we don't have free will. Your point however applies to his basic explanation of 'why we're here', as survival machines of replicating molecules.

  2. I must have misread/forgotten Dawkins' argument. Off to reread 'The Selfish Gene'.

    On an utterly different note, another example of not-coming-to-terms with the Copernican revolution - astronomers use the Parsec as a measure of distance. This is the distance at which a star has a parallax of 1 arcsecond. And it's based on the (diameter of the) Earth's orbit around the Sun. One parsec is equal to 4.2 lightyears; a lightyear is a much more 'universal' constant as it only depends on the speed of light.